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The fission fragment angular momenta can generally be expressed in terms of the six normal modes of rotation for the dinucleus and different models populate those modes to different degrees reflecting the mechanisms involved. For the nucleon exchange mechanism, the characteristic time scales for the various modes are discussed, leading to the expectation that the wriggling mode is fully populated, while twisting is unlikely to play a major role; bending probably has some presence which increases with mass asymmetry. Subsequently it is discussed how information about the fragment spin directions can be determined by observation of E2 emissions in even-even nuclei. It is shown how the yield ratio Y (0°)/Y (90°) in a modern Wilhelmy-type experiment can reveal the degree of twisting, a measurement that could be readily carried out now. Furthermore, with a view towards the future when the required technology has been developed, it is illustrated how the relative role of positive modes (wriggling) and negative modes (bending and twisting) can be determined by measuring the opening angle between two E2 photons whose helicities are also identified.

As a fissioning nucleus approaches scission, the angular-momentum bearing modes in the evolving dinuclear complex may be agitated by multiple transfers of individual nucleons. It is discussed how this mechanism populates the various rotational modes at different rates and leads to fragment angular momenta that are preferentially perpendicular to the fission axis but mutually largely uncorrelated. Using the fission simulation code FREYA, it is demonstrated how a measurement of the angular distribution of photons from identified collective transitions in the product nuclei can provide quantitative information on the relative importance of the twisting mode in fission.

We review recent work examining the influence of fission in rapid neutron capture (r-process) nucleosynthesis which can take place in astrophysical environments. We briefly discuss the impact of uncertain fission barriers and fission rates on the population of heavy actinide species. We demonstrate the influence of the fission fragment distributions for neutron-rich nuclei and discuss currently available treatments, including recent macroscopic-microscopic calculations. We conclude by comparing our nucleosynthesis results directly with stellar data for metal-poor stars rich in r-process elements to consider whether fission plays a role in the so-called ‘universality’ of r-process abundances observed from star to star.

OBJECTIVE: To compare two different methods of assessing binge eating in a sample of 128 obese women enrolled in a weight loss protocol. METHOD: Prior to treatment, participants completed the Binge Eating Scale (BES) and the Questionnaire on Eating and Weight Patterns (QEWP), as well as measures of other relevant constructs. They were then classified as bingers and nonbingers by each method and chance-corrected agreement was calculated. RESULTS: The BES and QEWP identified a small and nearly equal number of subjects as having significant binge eating, but there was only modest overlap between the two groups (kappa of .45). Subgroup comparisons revealed fundamental differences between the BES and QEWP in the assessment of the critical and associated features of binge eating. DISCUSSION: The relative merits of these two approaches to classifying binge eaters and implications for the design of new methods are discussed. [ABSTRACT FROM AUTHOR]

The event-by-event fission model FREYA is employed to study photon observables. The model has been expanded beyond the simple statistical photon emission reported previously to include the discrete RIPL-3 lines. We update the earlier results and discuss the sensitivity of the results to the FREYA input parameters.

Within the framework of the fission event generator FREYA, we are studying the sensitivity of various neutron observables to the yield distribution Y (A,Z,TKE) used as input to the code. Concentrating on spontaneous fission of 252Cf, we have sampled a large number of different input yield functions based on χ2 fits to the experimental data on Y (A) and Y (TKE|A). For each of these input yield distributions, we then use FREYA to generate a large sample of complete fission events from which we extract a variety of neutron observables, including the multiplicity distribution, the associated correlation coefficients, and its factorial moments, the dependence of the mean neutron multiplicity on the total fragment kinetic energy TKE and on the fragment mass number A, the neutron energy spectrum, and the two-neutron angular correlation function. In this way, we can determine the variation of these observables resulting from the uncertainties in the experimental mesurements. The imposition of a constraint on the resulting mean neutron multiplicity reduces the variation of the calculated neutron observables and provides a means for shrinking the uncertainties associated with the measured data.

Abstract Background In the absence of current cumulative dietary exposure assessments, this analysis was conducted to estimate exposure to multiple dietary contaminants for children, who are more vulnerable to toxic exposure than adults. Methods We estimated exposure to multiple food contaminants based on dietary data from preschool-age children (2–4 years, n=207), school-age children (5–7 years, n=157), parents of young children (n=446), and older adults (n=149). We compared exposure estimates for eleven toxic compounds (acrylamide, arsenic, lead, mercury, chlorpyrifos, permethrin, endosulfan, dieldrin, chlordane, DDE, and dioxin) based on self-reported food frequency data by age group. To determine if cancer and non-cancer benchmark levels were exceeded, chemical levels in food were derived from publicly available databases including the Total Diet Study. Results Cancer benchmark levels were exceeded by all children (100%) for arsenic, dieldrin, DDE, and dioxins. Non-cancer benchmarks were exceeded by >95% of preschool-age children for acrylamide and by 10% of preschool-age children for mercury. Preschool-age children had significantly higher estimated intakes of 6 of 11 compounds compared to school-age children (p Conclusions Dietary strategies to reduce exposure to toxic compounds for which cancer and non-cancer benchmarks are exceeded by children vary by compound. These strategies include consuming organically produced dairy and selected fruits and vegetables to reduce pesticide intake, consuming less animal foods (meat, dairy, and fish) to reduce intake of persistent organic pollutants and metals, and consuming lower quantities of chips, cereal, crackers, and other processed carbohydrate foods to reduce acrylamide intake.

Abstract Background Exposure to toxic chemicals in the home is a growing concern. This report presents an overview of the recruitment, methods for data collection, instruments used to collect data, and participant demographics for a study examining behaviors that influence exposure to environmental toxins in the home environment, also known as SUPERB (Study of Use of Products and Exposure Related Behaviors). Methods The methods involved three different platforms: telephone interviews, internet-based surveys, and home-based monitoring. The purposes of SUPERB were: first, to compare data collection platforms with regard to feasibility, acceptability and reliability; and second, to provide longitudinal population-based data characterizing seasonal and long-term changes in exposure-related behaviors including food consumption, temporal-spatial activity, and household product use. Results Two cohorts of households were enrolled: families (one parent and one child) from northern California and older individuals (age 55+) from central California. Parents (n = 499) in Northern California families were on average 36 years of age, 47.1% were Latino or nonwhite, and 10.2% took the survey in Spanish. Most of the children enrolled (n = 566) were under 6 years (82.7%). The older adults enrolled (n = 156) were, on average, 66 years of age and 23.7% were Latino or nonwhite, but only 2.6% completed the survey in Spanish. Conclusions We found that oversampling was successful in improving recruitment of under-represented subgroups, such as those with low education, thereby increasing diversity of our study sample. Protocols that minimize participant time, e.g., use of bar scanners and scales rather than questionnaires regarding use of household products, and the implementation of these protocols by staff who built relationships of trust, resulted in high retention over a longitudinal data collection scheme. A relatively small fraction of those who volunteer for longitudinal internet surveys are consistent in filling them out. Future reports will provide critical information on cross-sectional, seasonal and longitudinal patterns of exposure related behaviors in young children, parents of young children, and older adults.

Nitronaphthalene derivatives (NNDs) are among the most abundant volatile nitro-polycyclic aromatic hydrocarbons found in the Earth's atmosphere. Investigations of the atmospheric degradation processes show that photolysis is the major degradation pathway under ambient conditions. In this contribution, we present photochemical measurements and quantum-chemical calculations of three major NNDs. It is shown that the magnitude of the photodegradation and triplet quantum yields in 1-nitronaphthalene (1NN), 2-methyl-1-nitronaphthalene (2M1NN), and 2-nitronaphthalene (2NN) are inversely related to each other. In accord with a recent time-resolved and computation study (J. Phys. Chem. A 2013, 117, 6580) and in order to explain this striking observation we propose that these photochemical yields are largely controlled by (1) the conformational heterogeneity of the nitro-aromatic torsion angle, (2) the energy gap (spin-orbit coupling interaction) between the excited singlet state and the receiver triplet state, and (3) the topology of the excited singlet state in the Franck-Condon region of configuration space sampled at the time of excitation. A distribution of torsion angles closer to 90° leads to a higher photoreactivity. Methylation of the ortho position in 1NN to give 2M1NN increases the photoreactivity by 97%, while 2NN is largely photoinert. Conversely, the triplet yield decreases as the distribution of torsion angles gets closer to 90°: 0.93 ± 0.15 in 2NN, 0.64 ± 0.12 in 1NN, and 0.33 ± 0.05 in 2M1NN. These results suggest an important relationship between conformational heterogeneity and the photochemical fate of these NNDs. This structure-photoreactivity relationship is of relevance to current efforts aimed at modeling and understanding the distribution patterns of NNDs in the atmosphere and their overall contribution to air quality.

2-Aminopurine is a fluorescent probe widely used to study local dynamics as well as charge and energy transfer reactions in DNA/RNA. Despite its broad utilization, the nonradiative relaxation pathways responsible for the variation in its fluorescence quantum yield and fluorescence lifetime in different solvents are still under scrutiny. In this work we use steady-state absorption and emission spectroscopy and broad-band transient absorption covering the time scale from femtoseconds to microseconds to investigate the excited-state dynamics of 2-aminopurine 2'-deoxyriboside (2APdr) in acetonitrile, ethanol, and aqueous buffer solution at pH 7. It is shown that up to ~40% of the initial excited-state population decays by intersystem crossing to the triplet state depending on the solvent used, thus competing effectively with fluorescence emission. Furthermore, the rate of formation and yield of the triplet state depend sensitively on the hydrogen-donor ability and polarity of the solvent.

Femtosecond transient absorption experiments and density functional calculations are presented for 2-methyl-1-nitronaphthalene, 2-nitronaphthalene, and 1-nitronaphthalene in cyclohexane and acetonitrile solutions. Excitation of 2-methyl-1-nitronaphthalene at 340 nm populates the Franck-Condon singlet state, which bifurcates into two barrierless decay channels with sub-200-fs lifetimes. The primary decay channel connects the Franck-Condon singlet excited state with a receiver triplet state, whereas the second, minor channel involves conformational relaxation to populate an intramolecular charge-transfer state, as previously reported for 1-nitronaphthalene (J. Chem. Phys. 2009, 113, 224518). Conversely, the experimental and computational data for 2-nitronaphthalene shows that almost the entire Franck-Condon singlet excited-state population intersystem crosses to the triplet state in less than 200 fs due to a sizable energy barrier of ca. 5 kcal/mol that must be surmounted to access the intramolecular charge-transfer state. Our results lend support to the idea that the probability of population transfer to the triplet manifold in these nitronaphthalene derivatives is controlled not only by the small energy gap between the Franck-Condon singlet excited state and the receiver triplet state but also by the region of configuration space sampled in the singlet excited-state potential energy surface at the time of excitation. It is proposed that the ultrafast intersystem crossing dynamics in these nitronaphthalene molecules most likely occurs between nonequilibrated excited states in the strongly nonadiabatic regime.

Femtosecond-to-microsecond broadband transient absorption experiments are reported for Cy(3)PAu(2-naphthyl) (1), (Cy(3)PAu)(2)(2,6-naphthalenediyl) (2), and (Cy(3)PAu)(2)(2,7-naphthalenediyl) (3), where Cy = cyclohexyl. Global and target analyses of the data, based on a sequential kinetic model, reveal four spectral components. These components are assigned to (1) excited state absorption (ESA) of the ligand-centered S(1) state; (2) ESA of a receiver ligand-to-metal or metal-to-ligand charge transfer triplet state (τ(1) ≤ 300 fs); (3) ESA of the vibrationally excited, ligand-centered T(1) state (τ(3) = 7-10 ps); and (4) ESA of the relaxed T(1) state. Intersystem crossing (ISC) occurs in hundreds of femtoseconds, while internal conversion (IC) in the triplet manifold is slow (τ(2) ≈ 2 ps). The relaxed T(1) state shows biphasic decay kinetics in 2 and 3 with lifetimes of hundreds of picoseconds and hundreds of nanoseconds in air-saturated conditions, while only monophasic decay is observed in 1 under identical conditions. The primary decay pathway of the T(1) state is assigned to quenching by O(2), while the secondary channel is tentatively assigned to self-quenching or triplet-triplet annihilation. The ISC rate in 1 is not modulated significantly by the incorporation of a second heavy-atom group effecter. Instead, the position at which the second Au(I)-phosphine group is attached plays a noticeable role in the ISC rate, showing a 3-fold decrease in that of 2 compared to that of 3. The results challenge the conventional view that the rate of IC is larger than that of ISC, lending further support to the emerging kinetic model proposed for other transition-metal complexes. Gold(I) now joins the exclusive group of transition metals known to form organometallic complexes exhibiting excited-state nonequilibrium dynamics.

Salbutamol is a potent β(2)-adrenergic receptor agonist widely used in the treatment of bronchial asthma and chronic obstructive pulmonary disease. An increasing number of studies have detected salbutamol in natural water systems worldwide. Studies have shown that sunlight degrades salbutamol resulting in the formation of products; some showing higher toxicity to bacteria Vibrio fischeri than the parent compound. In this contribution, steady-state absorption and emission techniques, high-performance liquid chromatography, and transient absorption spectroscopy are used to investigate the photochemistry of salbutamol in aqueous buffer solutions at controlled pH values. Ground- and excited-state calculations that include solvent effects are performed to guide the interpretation of the experimental results. Salbutamol is sensitive to UVB light absorption in the pH range from 3 to 12, forming products that absorb light at longer wavelengths than the parent compound. Quantum yields of degradation reveal that the deprotonated species is 10-fold more photo-active than the protonated species. In line with this result, the fluorescence quantum yield of the protonated species is more than an order of magnitude higher than that of the deprotonated species. Transient absorption spectroscopy shows that population of the triplet state occurs with a rate constant of 7.1×10(8)s(-1) in the protonated species, while a rate constant of 1.7×10(10)s(-1) is measured for the deprotonated species. While degradation of the deprotonated species is not affected by the presence of molecular oxygen, a twofold increase in the photodegradation yield of the protonated species in air-saturated conditions is observed., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

The electronic energy relaxation of 1-nitronaphthalene was studied in nonpolar, aprotic, and protic solvents in the time window from femtoseconds to microseconds. Excitation at 340 or 360 nm populates the Franck-Condon S(1)(pipi( *)) state, which is proposed to bifurcate into two essentially barrierless nonradiative decay channels with sub-200 fs lifetimes. The first main decay channel connects the S(1) state with a receiver T(n) state that has considerable npi( *) character. The receiver T(n) state undergoes internal conversion to populate the vibrationally excited T(1)(pipi( *)) state in 2-4 ps. It is shown that vibrational cooling dynamics in the T(1) state depends on the solvent used, with average lifetimes in the range from 6 to 12 ps. Furthermore, solvation dynamics competes effectively with vibrational cooling in the triplet manifold in primary alcohols. The relaxed T(1) state undergoes intersystem crossing back to the ground state within a few microseconds in N(2)-saturated solutions in all the solvents studied. The second minor channel involves conformational relaxation of the bright S(1) state (primarily rotation of the NO(2)-group) to populate a dissociative singlet state with significant charge-transfer character and negligible oscillator strength. This dissociative channel is proposed to be responsible for the observed photochemistry in 1-nitronaphthalene. Ground- and excited-state calculations at the density functional level of theory that include bulk and explicit solvent effects lend support to the proposed mechanism where the fluorescent S(1) state decays rapidly and irreversibly to dark excited states. A four-state kinetic model is proposed that satisfactorily explains the origin of the nonradiative electronic relaxation pathways in 1-nitronaphthalene.

Background: Previous studies showed that resting energy expenditure (REE) is lower in obese African American women than in obese white women. It is unknown, however, whether there are racial differences in how REE responds to weight loss and energy restriction., Objective: We assessed REE, body composition, and respiratory quotient before and after weight loss in obese black and white women., Design: We measured REE by indirect calorimetry and body composition by densitometry before and after 20-24 wk of treatment with a 3870-4289-kJ/d diet. Subjects were 109 obese females (24 black, 85 white) with a mean (+/-SD) body mass index (in kg/m2) of 36.3+/-5.0, weight of 95.7+/-12.6 kg, and age of 42.3+/-8.1 y., Results: Before treatment, REE, adjusted for body composition, was significantly lower in black than in white subjects (P = 0.001). Black subjects lost significantly less weight during treatment than did white subjects (13.4+/-5.9 kg or 14.2+/-5.7% compared with 16.4+/-5.6 kg or 17.0+/-5.7%, respectively; P = 0.04). Analyses that controlled for initial REE and changes in fat mass and fat-free mass showed that blacks had significantly greater decreases in REE after treatment than did whites (9.9+/-7.3% compared with 6.3+/-7.4%; P = 0.02)., Conclusion: This study suggests that weight loss results in greater reductions in REE in obese black women than in obese white women. These data underscore the need to consider both biological and behavioral factors when setting expectations and assessing outcomes for obesity treatment in African American women.

Objective: To assess weight loss, as well as the prevalence of valvular heart disease, in 21 obese women who completed 2 years of treatment by fenfluramine and phentermine (fen-phen) in June 1997., Research Methods and Procedures: Patients were 21 of 22 women who had completed a 1-year, open-label trial of fen-phen combined with lifestyle modification. This study describes the results of a second year of treatment. The presence of valvular heart disease, defined as aortic regurgitation of mild or greater severity and/or mitral regurgitation of moderate or greater severity, was assessed using two-dimensional, color Doppler and pulsed- and continuous-wave Doppler examinations., Results: At 2 years, the 21 patients had a mean reduction in initial weight of 13.9 + 10.0%, which was significantly (p<0.001) smaller than their 1-year loss of 17.1 +/- 8.7%. Nine of 21 patients reported that they took fen-phen irregularly during the last 4 months of the study because of fears of developing health complications. These nine patients had a 2-year weight loss of 8.7 +/- 7.5%, compared with a significantly (p<0.04) larger loss of 17.6 +/- 10.5% for participants who reported taking medication regularly. Six of 20 (30%) patients met criteria for valvular heart disease. None of the six had signs or symptoms of this condition., Discussion: Fenfluramine was withdrawn from the market on September 15, 1997 because of concerns that it was associated with valvular heart disease. The present findings are discussed in terms of the potentially favorable long-term benefits of combining lifestyle modification with weight loss medications that are both safe and effective.

This study reports results 1 year after treatment for 77 obese women who had been treated for 48 weeks by diet combined with supervised (a) aerobic exercise, (b) strength training, (c) aerobic plus strength training combined, or (d) no exercise. Mean (+/- SD) end-of-treatment weight losses for the 4 conditions ranged from 13.5 +/- 9.1 kg to 17.3 +/- 10.3 kg, but there were no statistically significant differences among groups. Participants in all 4 conditions regained approximately 35% to 55% of their weight loss in the year after treatment; again, there were no significant differences among groups. Participants, however, who reported exercising regularly in the 4 months preceding the follow-up assessment regained significantly less weight than did nonexercisers.

This study examined a new method of providing brief, individual lifestyle modification to obese individuals treated by pharmacotherapy. Twenty-six women with a mean (+/- SD) age of 47.0 +/- 7.2 years, weight of 97.6 +/- 13.0 kg, and body mass index of 36.5 +/- 5.0 kg/m2 were prescribed 60 mg/d of fenfluramine and 15 mg/d of phentermine for one year. In addition, half of the women were randomly assigned to traditional group behavior modification, conducted by a nutritionist, which included 32 75-minute sessions during the year. The other half were provided lifestyle modification by a physician during 10 15-20 minute structured visits. All participants received identical treatment manuals and comparable assignments for behavior change. At the end of one year, patients in the physician group achieved the same highly successful weight losses as those treated by group behavior modification (13.9 +/- 9.6 kg vs. 15.4 +/- 7.9 kg, respectively). Treatment was associated with highly significant improvements in lipids and lipoproteins, as well as in mood and several measures of appetite. Weight loss the first four weeks, as well as patient completion of daily food records during the first 18 weeks, correlated positively with weight loss at weeks 18, 26, and 52. Results of this study await replication using larger samples but strongly suggest that effective lifestyle modification can be provided during brief, structured physician visits. The findings are discussed in terms of their implications for the treatment of obesity in primary care practice.

Body image, as measured by the Appearance Evaluation and Body Areas Satisfaction scales of the Multidimensional Body-Self Relations Questionnaire (T.F. Cash, 1994b), was assessed in 59 obese women before, during, and after 48 weeks of weight loss treatment. Before treatment, positive ratings of body image were associated with higher levels of self-esteem, lower levels of dysphoria, and fewer previous diets. After 24 weeks and a mean weight loss of 19.4 kg (SD = 6.5), participants showed significant (p < .0001) improvements in body image. A small weight gain from Week 24 to Week 48 was associated with a slight but significant worsening in both measures of body image. Nevertheless, after 48 weeks and a mean weight loss of 16.3 kg (SD = 7.1), body image was significantly improved from baseline (p < .0001). Changes in body image were not related to changes in weight. Future studies are needed to separate the effects of treatment and weight loss on body image in obese persons.

This study investigated changes in body composition, resting energy expenditure (REE), appetite, and mood in 128 obese women who were randomly assigned to 1 of 4 treatment conditions: diet alone, diet plus aerobic training, diet plus strength training, or diet combined with aerobic and strength training (i.e., combined training). All women received the same 48-week group behavioral program and were prescribed the same diet. Exercising participants were provided 3 supervised exercise sessions per week for the first 28 weeks and 2 sessions weekly thereafter. Participants across the 4 conditions achieved a mean weight loss of 16.5 +/- 6.8 kg at Week 24, which decreased to 15.1 +/- 8.4 kg at Week 48. There were no significant differences among conditions at any time in changes in weight or body composition. Women who received aerobic training displayed significantly smaller reductions in REE at Week 24 than did those who received strength training. There were no other significant differences among conditions at any time on this variable or in changes in appetite and mood.

Expert panels and governmental guidelines now recommend that obese persons seek modest (i.e., "reasonable") reductions in body weight rather than striving for "ideal" weights. Little is known, however, about patients' views of what is a "reasonable" weight loss. This study assessed patients' goals, expectations, and evaluations of various outcomes before, during, and after 48 weeks of treatment. Before treatment, 60 obese women (99.1 +/- 12.3 kg; body mass index of 36.3 +/- 4.3 kg/ m2) defined their goal weight and 4 other weights: "dream weight"; "happy weight"; "acceptable weight"; and "disappointed weight." Goal weight averaged a 32% reduction in body weight. A 17-kg weight loss was defined as disappointed; a 25-kg loss, was acceptable. After 48 weeks of treatment and a 16-kg weight loss, 47% of patients did not achieve even a disappointed weight. These data illustrate the dramatic disparity between patients' expectations and professional recommendations and the need to help patients accept more modest weight loss outcomes.

The prevalence of obesity among African American women approaches 50% and greatly exceeds rates for Caucasian women. In addition, black women lose less weight than white during obesity treatment and gain more weight when untreated. This study assessed resting energy expenditure (REE) and body composition in obese white (n = 122) and black (n = 44) women to explore the relationship between biological variables and these observed differences. REE and body composition were assessed by indirect calorimetry and densitometry, respectively, before weight loss. REE was significantly lower in black subjects (1637.6 +/- 236.9 kcal/d) than in white (1731.4 +/- 262.0) (p = 0.04). REE remained significantly lower in blacks than whites after adjusting for body weight (p = 0.02). REE, adjusted for fat-free mass, was also significantly lower in blacks than whites (p < 0.0001), although the overestimation of fat-free mass by densitometry in blacks may have contributed to this finding. There were no differences between the groups in respiratory quotient. These results suggest that a decreased REE may exist in obese black women, and it may be related to the observed differences between black and white women in the prevalence of obesity and in the response to weight loss treatment. These cross-sectional findings await confirmation in longitudinal studies.

This study prospectively assessed the psychological effects of weight loss and regain (i.e., weight cycling) in obese women. Measures of mood, binge eating, restraint, disinhibition, and hunger were obtained from 55 participants at baseline, after 6 months of treatment, and 58 months posttreatment. Women lost 21.1 +/- 8.4 kg after 6 months of treatment but were 3.6 +/- 10.9 kg above baseline weight at the time of the follow-up. Contrary to expectations, after this 21-kg cycle of weight loss and regain, women reported significant improvements in mood and binge eating, as well as reductions in hunger and disinhibition. Restraint was unchanged from baseline to follow-up. These data suggest that weight loss and regain are not associated with long-term adverse psychological effects. The findings also confirm earlier reports of significant weight regain after treatment and underscore the need for research to improve the maintenance of weight loss.

Participants were 130 obese women with a mean age of 41.1 +/- 8.4 years and a mean weight of 97.9 +/- 13.5 kg, who reported having undertaken a mean lifetime total of 4.7 +/- 1.2 major diets on which they had lost a mean total of 45.9 +/- 21.4 kg. Participants with a severe history of weight cycling had a significantly younger age of onset of their obesity than did mild cyclers and reported initiating dieting at a significantly younger age and lower weight. No evidence, however, was found that weight cycling was associated with greater reports of depression or other psychopathology; nor was it associated with a significantly greater frequency of binge eating disorder. The results are discussed in terms of the need to use additional measures of psychological functioning.

The Kva IgG2(k) myeloma protein showed a complete resistance to papain in the presence of cysteine at neutral pH, and a higher resistance to trypsin and alpha-chymotrypsin digestion than other IgG2 proteins. On the other hand, the Kva molecule was cleaved by pepsin at low pH to give the expected F(ab')2 fragment. When the cleavage conditions were altered, it was possible to obtain Fab, Fc, and Fc' fragments from this molecule as well. The Fab/c fragment and FacbFc' complex were also obtained, which have not previously been reported from human IgG2 molecules. Incubation at elevated temperatures (45-50 degrees C) and/or lower pH resulted mainly in enzymatic attack on the C terminal side of the hinge. It was necessary to destroy the hinge by reduction or to expose the Kva molecule at 70 degrees C or at lower pH (2.5) prior to digestion to facilitate enzyme digestion on the NH2 terminal side of the hinge. These results indicate that the hinge region of the Kva molecule has an unusually compact structure, which makes it extremely resistant to proteolysis.